Did I miss something while doing this dump?

[Thomas Jentzsch]

In Stella we are using $1260 as mask and compare to $220 and $240. Are you sure the extra bits in your mask make a difference?

[alex_79]

Yes, the logic on this board checks also A7 and A10.

[Thomas Jentzsch]

OK, so there is a difference to the original UA bankswitching.

 

And if I change the code to your values, Subterranea is working. Probably we have to split the bankswitching types.

Edited March 10, 2022 by Thomas Jentzsch

[alex_79]

Could that be the reason why "Subterranea" doesn't work? Maybe it accesses an address which is an hotspot in the extended UA scheme, but not in the one in this board that checks more bits.

[Thomas Jentzsch]

We two think alike.  

 

The problem in Subterranea is the very first, totally odd instruction: eor $4b44. It is executed only once when the cart is inserted. The code is in the Imagic original too. So it is not related to bankswitching. Together with the opcode of the following JMP instruction, the bytes read MDKL. I wonder if that's related to the programmer Mark Klein.

 

Ha, his name is Mark D. Klein! 

 

What an odd collision of hidden initials and modified bankswitching!

Edited March 10, 2022 by Thomas Jentzsch

[alex_79]

It's also quite cool that the initials of a 2600 programmer correspond to valid 6502 code...

[spadovan]

On 3/10/2022 at 7:12 PM, alex_79 said:

Thanks for posting the rom and the pictures of the board. The firs part of the rom is identical to the one posted before, and all the games in the second part seem to work fine with the generalized UA scheme in Stella.

eu que agradeço pela paciencia e tempo para responder, era o minimo que poderia fazer, postar os arquivos.
Eu já tinha testado antes de postar eles, mas para mim no stella em minha versão mais antiga 4.7.2 só funciona em 0840.

 

I thank you for your patience and time to respond, it was the least I could do, post the files.
I had already tested them before posting them, but for me on stella in my older version 4.7.2 it only works on 0840.

On 3/10/2022 at 7:12 PM, alex_79 said:

I quickly checked the traces in the pictures, and looks like the bankswitching logic is identical to the one of the board shown in this thread:

Vou olhar

 

I will look

[Thomas Jentzsch]

I had a closer look at Mania's Subterranea to find out why it wouldn't work in Stella. It I found a 2nd spot, where the current Stella UA emulation fails. In bank 0 the following code can be found:

 

 

This is used for correct timing. And with Stella's UA bankswitching, the last instruction causes another unwanted bank switch. Maybe this explains why additional bits are checked in the Mania ROMs. 

 

So for now it seems like there where at least two different bankswitching types used in Brazil. One that is close to UA bankswitching and one that checks more bits. I wonder if even more types exist.

[Thomas Jentzsch]

On 7/26/2019 at 3:24 PM, alex_79 said:

Probably Stella can't autodetect the type of cartridge.

Yes, in case of multi game ROMs, you have to tell Stella the number of ROMs. It will then try to auto detect the type of each individual game.